Download Sedimentary Geology of Coastal-Transitional and

GEOS2016 Singapore - Keynote Address
Sedimentary Geology of Coastal-Transitional and Shallow-Marine
Depositional Environments and Rock Successions: Lessons from the
Recent, Holocene and Tertiary
by
Abdul Hadi bin Abd Rahman
Department of Geosciences, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak Darul
Rizuan, Malaysia
ABSTRACT
Coastal-transitional and shallow marine environments are geomorphic zones that are very
important to human civilization. Today, a large percentage of the world’s population is
concentrated within the coastal-transitional zone. Many modern major cities are built near
coastlines. Major human economic activities such as fishery, shipping, waste disposal and
tourism are reliant on the well-being of coastal and shallow marine zones. Historically, many
important civilizations are centered on coastal plains, and are closely associated to the shallow
seas. These geographic regions have been very important in the past, and remain very important
today and also in the future, to human society.
The coastal-transitional and shallow marine environments are located at the interface and
interaction zone between three major earth’s surface systems – atmosphere, ocean and land. As
such, these zones host some of the most dynamic, natural, surface environments. In addition,
many human activities along the coasts modify the way natural systems operate, through
pollution, siltation, dredging, and construction of man-made structures. The high and
continuously increasing density of human population within these zones has intensified these
activities, and in one way or another, presents a new dimension of environmental threat to the
coastal ecosystems. Improving our scientific understanding of the dynamics of these
environments can improve the ways we interact and manage its well-being.
Global warming and sea level rise is one major cause of coastal erosion. While the rise in
global temperature is well evidenced, and the corresponding rise in eustatic sea level is widely
seen as the main cause of worldwide coastal erosion, the rate of sea level rise remains uncertain
(Stive, 2004; Zhang et al., 2004). The Holocene is the epoch recording the last 11,700 years of
GEOS2016 Singapore - Keynote Address
the earth’s history. This relative warm inter-glacial period records the longest warm stable
period since the last 400,000 years (Petit et al., 1999). Holocene climatic, environmental and
sea level change has been responsible in the shaping of modern coastal-transitional and shallow
marine environments around the globe. The sediments deposited during this period cover the
largest surface area of the globe. The Holocene coastal sedimentary successions of Perak,
Malaysia was studied by the author to understand how the Holocene climate change and sea
level rise has affected the development of the coastal plain and coastline. Understanding these
changes may allow a better understanding of the impact of future global warming and sea level
rise on coastal-transitional environments.
The understanding of coastal-transitional and shallow marine environments is not only
important in the context of managing modern environments for the human population, it has also
been important in the extraction of minerals and fossil fuel in the subsurface. Most of the oil and
gas in South East Asia are extracted from known Tertiary coastal marine rock successions in the
deep subsurface. Many studies on the Neogene coastal and shallow marine successions have
been carried out in Malaysia in relation to the oil and gas industry.
This paper highlights the author’s personal experience and interest on the coastal-transitional
and shallow marine environments, and its corresponding rock successions. The author, as a
sedimentary and petroleum geologist, has been involved in the following researches:
i.
Modern coastal and shallow marine environments – with a case study on the
modern Pahang delta (Figure 1);
ii.
Holocene sea level change and the development and evolution of coastal and
shallow marine environments – with a case study on the Perak coastal-deltaic
plain succession and coastline;
iii.
Sedimentology and stratigraphy of the Neogene (Tertiary) coastal and shallow
marine sedimentary successions– with a case study on the generally Miocene
Nyalau Formation in Sarawak.
The result from these studies highlight the importance of researches on coastaltransitional and shallow marine environments, in managing modern environments, forecasting
future challenges of sea level rise and in the extraction of fossil fuel, for the betterment of
GEOS2016 Singapore - Keynote Address
mankind. This paper also lists recommendations on future directions in coastal-transitional and
shallow marine environments research.
a
b
Figure 1. Three images of the Pahang coastline acquired from MACRES; these images are from the year:
(a) 1988, (b) 1995 and (c) 2000. All the three images display the development of a broad strand-plain,
wave-dominated beach in the north, while the southern flank of the delta is marked by a barrier-sheltered,
tide-influenced lagoon (Courtesy of MACRES, Malaysia).
References
Petit, J.R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, J.-M., Basile, I., Bender, M.,
Chappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V.M., Legrand, M.,
Lipenkov, V.Y., Lorius, C., Pepin, L., Ritz, C., Saltzman, E., Stievenard, M., 1999.
Climate and atmospheric history of the past 420,000 years from the Vostok ice core,
Antarctica. Nature 399, 429–436.
Zhang, K., Douglas, B. C. and Leatherman, S. P., 2004. Global Warming and Coastal Erosion.
Climate Change, 64, 41-58.
Stive, M. J. F., 2004. How important is global warming for coastal erosion – An editorial
comment. Climate Change, 64, 27-39.
c